This invention relates to a multiple panel building closure useful for self-supporting walls and roofs.
Most panel type wall and roof structures are not self-supporting and depend upon either some form of sheathing beneath or at least some substantial frame support. Because of the dimensional variations of such panels it is difficult to interlock them or to seal them edge to edge and obtain a desired hermetical seal that is both waterproof and of a strength comparable to the strength of the panel for support purposes.
The cutting of panels from natural wood or board products, and the molding or extruding of panels from various materials has not been conducive to the production of multiple panel closures due to the impossibility of maintaining the required dimensional tolerances for proper joinder of the panels.
Some processes of molding and/or extrusion of panels are limited to the use of materials that lack the desired strength and whereby the incorporation of reinforcing materials is impractical.
Attempts to utilize a polyester resin for panel construction as in Canadian Pat. No. 969,460 have required a sandwich type of rolled construction between cellophane carrier sheets and have tended to incorporate dimensional variation problems in the final product.